1. Field of the Invention
The present invention relates to a heat-dissipating fan housing and, more particularly, to a heat-dissipating fan housing with stationary blades.
2. Description of the Related Art
FIGS. 1 and 2 show a typical conventional heat-dissipating fan housing 80 including a casing 81 with a mounting portion 82 at an inner side thereof. An impeller 83 is coupled to the mounting portion 82 and can be driven by a drive 85 to rotate. The mounting portion 82 includes a plurality of stationary blades 84 forming a guiding device. Each stationary blade 84 extends in a radial direction surrounding the mounting portion 82 to guide airflows created by rotating the impeller 83, increasing the wind pressure of the airflows. The casing 81 further includes an air inlet 811 and an air outlet 812. Each stationary blade 84 is at an acute angle with a longitudinal axis of the casing 81 and includes a bottom edge 841 contiguous to and flush with the air outlet 812. However, there is no structure for concentrating the airflows leaving the air outlet 812 such that the airflows leave the air outlet 812 in different directions due to the acute angle between each stationary blade 84 and the longitudinal axis of the casing 81, resulting in noise and failing to effectively increase the wind pressure. Although, the bottom edge 841 of each stationary blade 84 may not be flush with the air outlet 812 due to uncertainties during manufacturing (such as tolerances of molds or manufacturing errors in quality control), the spacing between the bottom edge 841 of each stationary blade 84 and the air outlet 812 is still insufficient to guide and concentrate the airflows.
FIG. 3 shows another conventional heat-dissipating fan housing 90 including a casing 91 with an air inlet 911 and an air outlet 912. A plurality of stationary blades 92 is formed in an inner side of the casing 91 at regular intervals. A wing-shaped guiding member 93 is formed on an inner edge of the casing 91 and between two adjacent stationary blades 92. An impeller 94 is rotatably coupled to the casing 91. Each of the stationary blades 92 and the wing-shaped guiding members 93 includes a bottom edge 921, 931 adjacent to the air outlet 912. Operational noise is reduced by reducing turbulence passing through the stationary blades 92 through provision of the wing-shaped guiding members 93 and the stationary blades 92. An example of such a heat-dissipating fan is disclosed in Taiwan Invention Patent Publication No. 1276743 entitled “Fan Housing and Fans with Stationary Blades”. However, the wing-shaped guiding members 93 increase the overall manufacturing costs. Furthermore, although the bottom edge 931 of each wing-shaped guiding member 93 is not flush with the air outlet 912, the bottom edge 921 of each stationary blade 92 is flush with the air outlet 912 such that there is no structure in the inner side of the casing 91 at the area adjacent to the air outlet 912 for concentrating the airflows leaving the air outlet 912. Thus, the airflows created by rotating the impeller 94 leave the air outlet 912 in different directions, resulting in noise and adversely affecting the wind pressure increasing effect.